AWS MCP Server

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden. It partially compensates by disclosing return values (tag status, digest) since no output schema exists, but omits critical AWS-specific behaviors: pagination mechanics, read-only safety characteristics, and error cases (e.g., repository not found).

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Single efficient sentence with zero redundancy. Front-loaded action verb ('List') immediately clarifies operation type. No structural waste despite containing service name (ECR) and key capability hints.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Adequate for basic invocation but gaps remain for a cloud API tool. Missing pagination context (critical for AWS list operations), no authentication scope requirements, and no error handling guidance. Mention of return fields partially compensates for absent output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with detailed parameter descriptions provided. The description adds minimal semantic value beyond the schema—mentioning 'tag status' reinforces the filter parameter but adds no syntax clarification or usage examples. Baseline 3 warranted for high-coverage schemas.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Clear verb (List) and resource (ECR repository images) with specific output fields mentioned (tag status, digest). However, it fails to distinguish from sibling tool `aws_ecr_describe_images` which performs a similar but distinct operation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance provided on when to use this versus `aws_ecr_describe_images` (which retrieves detailed metadata vs. this paginated list). Also omits prerequisite context such as requiring existing repository or AWS credential configuration.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.